"We have to recover. It's tough for the players but mentally and physically we've got to recover, we've got to go again," McClaren told the club website (www.nufc.co.uk).
"It's a big test on Monday; I'm very, very interested to see how we react after (the Everton) game.
"Do we take the belief and confidence from our performance? Do we take it into Monday's game, which is a massive game?
"Like Robbie (Elliot) said before the (Everton) game, we've got two games in three days, we've got no excuses: let's go."
Defender Daryl Janmaat echoed the comments of his manager.
"I've never lost a game like that before but we have no time to be mad. The next game is less than 48 hours away and that may be good for us," Janmaat said.
"We have to recover, prepare and look forward to West Brom. We have to try and get a result there.
"It will be a tough game but there is no reason why we cannot win there. We did it last season so we know how it feels to win there, and we will remember that on Monday."
Newcastle are third from bottom in the league with 17 points from 18 matches.
(Reporting by Shravanth Vijayakumar in Bengaluru; editing by Amlan Chakraborty)
Share
